In game theory there is game called entrance deterrence. The idea is that when a person or firm challenges an incumbent it goes along two nodes of thought. The first is the challenger's decision to go against the incumbent. The second is whether the incumbent fights the challenger, or defers to him. This game will be able to predict both what Specter and what Bunning are doing this election season.
If the challenger decides not to play, his payout is 0 for the challenger and 2 for the incumbent. If the challenger decides to fight, then it's the incumbents turn to make a decision. If the incumbent fights then his payout will be -1 to the challengers 0, and if he defers to the challenger it will be a payout of 1 to each.
As two-bit challengers appear against incumbents from time to time, it should be clarified that this game only applies when two factors are present. The first is that the incumbent is in danger of losing his election either due to his low popularity, or his opponent's high popularity. The second factor is that there is gain from leaving the senate, such as a high paying job, or prestige of being a retired senator who didn't lose.
An example of this is the election of mark Warner. Last cycle John Warner was considering retirement, but wasn't sure. Mark Warner threw out hints that he would run. John could say that he will fight mark regardless of what mark does, but that is unlikely. The payoffs show that should mark run, and john fight, john will have a payout of -1, worse than his payout of 1 should he defer to mark, and retire gracefully.
This payout comes from john either losing a fierce election with mark, ending his long running senate career in disgrace, or eking out a bare win, where he will be in the extreme minority, and his reputation still varnished. Thus, when it became clear that john's plans not to retire were bluffs, he realized the most logical move would be to retire. This is what happened. If you replace mark with Toomey (scary I know) and Warner with specter, you have the reasons why specter will retire should Toomey run. There are variables of course, but if specter can't independents in the primary he will retire, soon after, or shortly before Toomey announces.
This should suggest that Bunning will retire, as a plausible republican challenger would defeat him, but there is a flaw in this plan. This all depends on logic, Bunning's potential challenger has to realize the payouts described above, as does Bunning. If Bunning is Crazy, and playing illogically, then the challenger won't play. Why bother running, when your payoff will be 0 either way. Either 0 for not running, or 0 for losing to bunning/winning but getting beaten up, to go onto lose to your democratic opponent. This is what bunning wants us to think.
I theorize that he understands this game and the payouts, that's why he has been playing up the whole "I'm crazy" shtick of late. He's trying to convince his opponents that he would not act logically at this game. That if he was challenged he might defer, he might fight, he might find a third option. Either way it would be better not to enter at all. The reasoning is that the number of votes he loses by acting crazy is less than that he'd lose by losing the primary (where the general election votes are irrelevant) or winning the primary bloodied up and broke.
This assumes that he's sane, eccentric, but sane. He has had a tendency to act weird, but the type of crazy being described here is not that of bunning. It suggests a sincere lack of logic, not simply acting weird. Take Bunning's performance back in 2004, it's weird, but not illogical. Considering his money, the partisan tilt of Kentucky, and the fact that bush was expected to do well, he probably figured he could phone it in. Lazy and stupid, but there was logic to it.
Furthermore, consider his recent acts of crazy. It's all stuff that only would anger liberals, and the political class. Suggesting that Ginsberg will die soon, picking fights with Cornyn and the NRCC, it's not the kind of stuff that would anger conservative primary voters. He's not expecting much help from either the political class or liberals to begin with, so there's little to nothing to lose by fighting with them. There is logic in his eccentricities.
This of course assumes that bunning is eccentric, but not illogical. If he is in fact crazy crazy then everything stated is wrong, but the only way to tell that is to wait until a challenger appears and see what he does. If he defers, then bunning is still logical, if he keeps on trucking, he's not. If no challenger appears then all we will know is that it worked.
Game theory has numerous applications in politics that are still being understood. This game shows why other politicians retired and will show why specter will retire. It will also do what few thought possible: explain Jim Bunning.